靶向静脉内皮生长因子（VEGF）/VEGF 受体，通过抗血管新生治疗，可治疗转移性透明细胞肾癌 （ccRCC），但其功效因患者而异。探究这种差异的原因，可以带来相关治疗靶点的识别。因此，我们研究了一些新型 VEGF 剪接变异体，其比传统的 VEGF 剪接异构体抑制效率低。通过序列分析，我们确定了 VEGF 基因末端的新型剪接受体，导致 VEGF mRNA 中插入了 23 bp 的碱基。这种插入可以改变 VEGF 蛋白质 C 端中已知的剪接异构体 VEGFXXX 前开放阅读框，在正常组织和 RCC 细胞系中分别通过 qPCR 和 ELISA 分析了这些新型 VEGF 剪接异构体（VEGFXXX/NF）的表达，并研究了 VEGF222/NF（相当于 VEGF165）在生理和病理血管生成中的作用。我们的体外数据表明，重组 VEGF222/NF 可以通过激活 VEGFR2 促进内皮细胞的增殖和血管通透性。此外，VEGF222/NF 的过度表达会增强 RCC 细胞的增殖和转移能力，而 VEFG222/NF 的下调会导致细胞死亡。我们还在小鼠体内植入 VEGF222/NF 过度表达的 RCC 细胞，生成了 RCC 的体内模型，并以多克隆抗VEGFXXX/NF 抗体治疗。VEGF222/NF 过度表达增强了具有侵袭性和完全功能的肿瘤的形成，而抗VEGFXXX/NF 抗体的治疗通过抑制肿瘤细胞增殖和血管生成，减缓了肿瘤生长。在 NCT00943839 临床试验的患者队列中，我们研究了血浆 VEGFXXX/NF 水平、抗VEGFR治疗抵抗和生存之间的关系。高血浆 VEGFXXX/NF 水平与更短的生存期和抗血管新生药物的低疗效相关。我们的数据证实了新的 VEGF 异构体的存在，这些异构体可以成为对抗抗 VEGFR 治疗抵抗的肾癌患者的新的治疗靶点。本文受版权保护，版权所有。

The efficacy of anti-angiogenic treatment by targeting VEGF/VEGF receptors in metastatic clear cell renal cell carcinoma (ccRCC) varies from patient to patient. Discovering the reasons behind this variability could lead to the identification of relevant therapeutic targets. Thus, we investigated novel splice variants of VEGF that are less efficiently inhibited by anti-VEGF/VEGFR targeting than the conventional isoforms. By in silico analysis we identified a novel splice acceptor in the last intron of the VEGF gene resulting in an insertion of 23 bp in VEGF mRNA. Such an insertion can shift the open reading frame in previously described splice variants of VEGF (VEGFXXX), leading to a change in the C-terminal part of the VEGF protein. Next, we analyzed the expression of these alternatively spliced VEGF new isoforms (VEGFXXX/NF.) in normal tissues and in RCC cell lines by qPCR and ELISA, and investigated the role of VEGF222/NF (equivalent to VEGF165) in physiological and pathological angiogenesis. Our in-vitro data demonstrated that recombinant VEGF222/NF stimulated endothelial cell proliferation and vascular permeability by activating VEGFR2. In addition, VEGF222/NF overexpression enhanced proliferation and metastatic properties of RCC cells, whereas downregulation of VEGF222/NF resulted in cell death. We also generated an in-vivo model of RCC by implanting RCC cells overexpressing VEGF222/NF in mice, which we treated with polyclonal anti-VEGFXXX/NF antibodies. VEGF222/NF overexpression enhanced tumor formation with aggressive properties and a fully functional vasculature , while treatment with anti-VEGFXXX/NF antibodies slowed tumor growth by inhibiting tumor cell proliferation and angiogenesis. In a patient cohort from the NCT00943839 clinical trial we investigated the relationship between plasmatic VEGFXXX/NF levels, resistance to anti-VEGFR therapy and survival. High plasmatic VEGFXXX/NF levels correlated with shorter survival and lower efficacy of anti-angiogenic drugs. Our data confirmed the existence of new VEGF isoforms that could serve as novel therapeutic targets in patients with RCC that are resistant to anti-VEGFR therapy.This article is protected by copyright. All rights reserved.